This study aimed to compare analgesic efficacy and the side effects of postoperative continuous epidural infusion (2 ml/hr) of morphine (40 µg/ml) or butorphanol (50 µg/ml) administered with 0.15% ropivacaine 100 ml.

Forty consenting, healthy, term parturients who had undergone Ceasarean section under epidural lidocaine and ropivacaine anesthesia received a morphine 1 mg bolus and 0.15% ropivacaine 100 ml/morphine 4 mg (Group M, n = 20) or a butorphanol 2 mg bolus and 0.15% ropivacaine 100 ml/butorphanol 5 mg (Group B, n = 20) using an epidural 2 day infuser (2 ml/hr) 30 minutes after surgical incision.

No significant difference were observed by the visual analog scale (VAS) for pain during rest, but Group B requested significantly greater amounts of supplementary diclofenac sodium during the first 24 hours. Side effects were higher in pruritus in Group M and in somnolence in Group B, but no significant differences in severe side effects were evident between the two groups.

Using 0.15% ropivacaine 100 ml with morphine (40 µg/ml) via an epidural 2 day infuser (2 ml/hr) provided better pain relief than butorphanol (50 µg/ml) group, but significant side effects, such as pruritus, were observed.